If the choice is Soft, Medium Soft, or Softest, whats the best bet?

How would any of the above compare in wear to a normal road tyre?

ALSO...

The ones with no water channels cut in them, they meant to be deadly in the wet, but is that just mean standing water, or even when the road/track is damp but no standing water?
I presume just when standing water as cant see how water channels make any difference if the grounds just damp but no puddles.